Mould carriers of the most various different types have been proposed and have been used for years for the production of polyurethane products. The mould halves are used in these mould carriers for the various products and the mould carriers bring about the opening and closing of the mould halves.
A carrying device for injection moulding and vulcanizing moulds has been proposed (German patent specification (Offenlengungsschrift) No. 2,020,363), which is provided with a lower carrier for accepting a lower mould and an upper carrier for accepting an upper mould, the two carriers being adjustably carried so that they can be arrested in different angular settings between the upper and lower mould. Owing to this adjustability the possibility is to be created of arranging the mould or, respectively, the mould cavity not only in the horizontal direction but also in a certain oblique position. In particular the lower carrier and the upper carrier can be swung through 90.degree. for opening and for closing the mould in relation to each other. The mould is adapted to be held locked in the closed position by a lever constructed as a pressure support, since the lever in the closed position for dead-centre locking is perpendicular to the direction of movement of an actuating member, which serves for opening and for closing the mould carrier. In this case the actuating member consists of a piston cylinder arrangement fixed pivotally underneath the mould carrier and connected via a two-armed lever linkage with the pressure support. The two-armed lever linkage has two tension struts running to the side of the mould carrier, something which is disadvantageous in terms of limiting the maximum size of the moulds which can be used with the mould carrier. Furthermore as regards the vertical height of the moulds which can be inserted into the mould carrier there is a limitation, since only one mould of a fixed vertical height can be inserted into the mould carrier. A further disadvantage is the non-linear movement of the actuating member, thereby eliminating the possibility of controlling opening and closing of the mould carrier in an automated plant using simple cams or ramps. Another disadvantage of the known mould carrier resides in that on opening the mould carrier there is the danger that mould parts, which have a substantial vertical dimension may be damaged inasmuch as, on opening the mould carrier the opening and pivoting movement runs along a circular path from the outset. The last mentioned disadvantage is admittedly dealt with by a modern development of the mould carrier in accordance with the U.S. Pat. No. 3,840,317, since a parallel stroke is arranged to take place before the circular pivoting movement on opening. However the other disadvantages still inherent in this more modern further development. The most convenient of the mould carriers as proposed to date are those described in the German patent specification (Offenlegungsschrift) No. 1,909,050. In one of the embodiments described in this specification an upper platen, carrying the upper mould half can be pivoted upwards through 90.degree. away from the lower platen carrying the lower mould half by means of a two-armed lever for opening and closing. The two-armed lever has its pivot point arranged on the mould carrier and is actuated by a toggle lever, which is pivoted on an actuating member. The actuating member which is arranged so as to project to the rear from the mould carrier, consists of a linearly shifting pin, on which the toggle lever is pivoted. The advantages of this known mould carrier reside more especially in that the linear movement of the actuating member, arranged behind the mould carrier, provides a favourable possibility for the control of the opening and closing movement. In the case of a stationary mould carrier the linear movement of the actuating member can be controlled by a piston cylinder arrangement. The toggle lever engaging the two-armed lever is so arranged that in the closed position of the mould carrier it is normal to the direction of movement of the actuating member so that a dead-centre locking of the mould carrier is brought about in the closed position.
A disadvantage in the case of this prior art mould carrier resides in that the upper mould half can only be pivoted away from the lower mould half. Such a pivoting movement is sufficient if simple articles with a small height are to be moulded. On the other hand in the case of complicated taller articles it is necessary to raise the upper mould half before effecting the "pivoting-away" movement through a fixed displacement in a parallel direction until the moulded product has come clear of the upper mould half, and it is only after this that the pivoting- or swinging-away movement can be begun. A further disadvantage resides in that the mould carrier is not adjustable for different moulds as regards height so that the mould carrier is generally not suitable for accepting moulds of different height.
Another very serious disadvantage resides in that the whole actuating mechanism extends for a very considerable distance to the rear by an amount which is approximately twice the depth of the mould. If control or operation using cams were to be considered it would then be necessary to provide an extremely expensive bearing arrangement owing to this great length of projection to the rear.
In the German patent specification No. 1,909,050 a second embodiment of the mould carrier is described wherein it is possible to raise the upper mould half in a guided parallel movement. The two-armed lever of this embodiment engages laterally on the upper platen of the mould carrier, since the point of engagement is constituted by a pin which can slide in a slot in order to make possible parallel guidance of the upper mould half despite the pivoting movement of the lever. In the case of this known mould carrier the upper mould half is admittedly raised in a parallel direction from the lower one; however pivoting into the 90.degree. position is not possible. Owing to the lateral connection or engagement of the two-armed lever furthermore the use of the mould carrier is considerably limited as regards the size of the moulds to be used. It is therefore only possible to use moulds up to a certain breadth as determined by the position of the two-armed lever connected on both sides. The vertical adjustment of the mould carrier is not possible either as is the case with the initially described embodiment so that it is not practicable either.